Complex foot deformity correction with conventional techniques has many limitations including neurovascular problems, skin problems, stiffness, and limb shortening. Ilizarov methodology on the contrary is not limited by deformity magnitude and permits a comprehensive approach to foot deformity correction treating all deformities simultaneously, either in foot or leg, combining techniques of soft tissue distraction, bone lengthening, and arthrodesis. Nevertheless, Ilizarov methodology is not exempted from problems and difficulties. It is a technically demanding procedure with a long learning curve. For the patient, treatment time is long, the frame is uncomfortable, pin infection is frequent, and other complication rates are also high. However, if proper technique is used including preoperative planning, preconstruction of the frame, careful ambulatory handling, and this method can be useful in the management of difficult cases and in certain circumstances, the sole method to correct complex foot deformities.

Keywords: Ankle, complex, deformity, foot, Ilizarov

How to cite this article:Lopes N. Use of Ilizarov methodology for complex foot and ankle problems: A personal experience. J Limb Lengthen Reconstr 2015;1:42-53

Complex foot deformity correction with conventional techniques, has many limitations including neurovascular problems, skin problems, stiffness and sacrificing foot and leg length. Ilizarov methodology on the contrary is not limited by deformity magnitude and permits a comprehensive approach to foot deformity correction treating all present deformities at the same time, either on foot or leg, combining techniques of soft tissue distraction, bone lengthening and arthrodesis. Nevertheless, Ilizarov methodology is not exempt of problems and difficulties. It is a technically demanding procedure with a long learning curve. For the patient, treatment time is long, the frame is uncomfortable, pin infection is frequent and other complication rate are also high.However, if proper technique is used including pre-operative planning, pre-building of the frame, careful ambulatory handling, this method can be a useful in the management of difficult cases and in certain circumstances, the sole method to correct complex foot deformities.

Preoperative planning

Planning is important in any surgical procedure, but it gets crucial if one intends to perform a percutaneous procedure, using the Ilizarov method.

A good planning begins with good plain radiographs, including all bone segments involved and the contiguous bone extremities in two orthogonal planes, and if necessary in two more oblique planes. It is advisable to get also plain radiographs of the contralateral bone segments to confirm the normal anatomy and guide the correction. Generally, those films are enough to plan the treatment, but in complex deformities, it is advisable to do two-dimensional or three-dimensional (3D) computed tomography (CT) scans.

Prebuilding of the apparatus

Preconstruction [1],[2] of the frame enables building a lighter, more comfortable frame and to reduce the surgical time, compared with the PERI Construction or Progressive construction method.

The basic frame building for foot deformities includes

A solid base from where all the moving pieces will take fulcrum

A posterior half-ring to correct the hindfoot deformity

An anterior half-ring to correct the forefoot deformity.

The base consists of a two-point fixation at the tibia and fibula, as widely spread as possible. On the frontal radiogram, one can calculate the point of insertion of the distal ring about 10 cm from the ankle and the proximal one, as high as possible but permitting full flexion of the knee. The two fixation points can be done with two rings or a ring and a bridge pin, half ring or arch [Figure 1]a-c],[3],[4],[5],[6],[7] depending on the needs in stability. The diameter of the rings can be calculated on the patient, measuring the larger diameter of the limb and adding 6 cm, or fitting on the limb a ring that overlaps a two-finger breadth, beneath inner edge and skin. The two fixation points are interconnected with three connecting rods. If more stability is needed as on heavy patients, one more rod is mounted. After the base assembly, it is checked on the patient's limb to confirm again for ring diameter and alignment with bone structures.

The rings are fixed to the bone with two wires inserted at more than 60° angular spread, one smooth wire, and a half pin at a right angle or two half pins, depending on soft tissue considerations [Figure 2]a, c, and d]. When two wires must be introduced with <60° angulation from each other, then olive wires are preferred [Figure 2]b]. If more stability is needed, more wires or half pins can be added.

The hindfoot correcting half ring is fixed to the calcaneum with the same slant of the deformity, utilizing two posterior pins at a 45° angle or a posterior pin and a transverse wire. This arch is connected to the base with two hinges, one lateral and other medial, centered on the upper cortex of the calcaneal tuberosity for a cavus correction or the lower cortex of the calcaneal tuberosity for an equinus correction. A motor rod is mounted posteriorly [Figure 3]a and b].

Figure 3: Placement of forefoot and hindfoot half rings and osteotomy configuration in adults with equinus deformity along with placement of motor rods and hinges

The forefoot correcting half-ring is fixed to the metatarsal bones with the same slant of the deformity, with two crossed wires, one through 5 th , 4 th , and 3 rd metatarsals and the other through the 1 st and 2 nd ones. This arch is connected to the base. For equinus or cavus, the hinges are located at the talar head. For a rocker bottom or plano-valgus foot, the hinges are centered on mid-tarsal bones. One anterior motor rods only is mounted for forefoot equinus alone. Two are mounted if supination/pronation need correction along with forefoot equinus [Figure 3]a and b].

Two motor rods can be mounted in between hindfoot and forefoot arches, if forefoot adduction-abduction needs correction [Figure 3]a and b].

In patients younger than 13-15 years of age, without destroyed or ankylosed foot joints; no osteotomy is needed and an unconstrained frame can be used for soft tissue distraction. The joint surfaces themselves guide the correction without need for specific hinges [Figure 4]a and b]. [8]

Figure 4: Placement of forefoot and hindfoot half rings in adolescents with equinus deformity. Note that no osteotomy is done and unconstrained frame is used if joints are not destroyed and there is no ankylosis

Correction of complex or pronounced deformities of the ankle, foot and forefoot needs stabilization of the toes and hallux by wires, which are fixed to the forefoot correcting arch [Figure 3]a and b].

The basic frame building for peri-articular ankle fractures includes

A base, as stated before

An anchoring point to fix the wires for reduction and fixation of peri-articular fragments

A bridge to the calcaneum to do the ligamentotaxis reducing effect or the arthrodiastasis protecting effect.

The anchoring point is a ring leveled and measured on the contralateral limb in a position aligned with the fractured zone and is attached to the base with three or four rods [Figure 5]a].

The bridge, composed by a hindfoot arch or a hindfoot and a forefoot arches connected by two plates, is also leveled and measured on the contralateral foot and fixed to the anchoring ring with three or four rods [Figure 5]b]. [9]

Figure 5: Placement of anchoring point and bridge in case of periarticular fractures

We apply the frame with the patient supine in a normal operating table. Percutaneous tenotomy and fasciotomy must be done on the main contracted structures, namely Achilles tendon and plantar fascia.

We use V-type osteotomy. The posterior arm runs from just anterior to calcaneal tuberosity aiming inferiorly in the middle of the calcaneum. The anterior arm runs from talar neck going inferiorly to join the inferior extent of the posterior arm. Provisional stabilization is done with Kirschner wires. The central part of the talus body must be fixed to the base with a wire tensioned between two rods with slight arthrodiastasis of the ankle joint [Figure 3]a].

The prebuilt frame is opened like a book, wrap around the limb, and aligned with the help of an image intensifier. One wire is inserted in each ring of the base and "fine tuning" is done. When proper fit is obtained, the remaining wires and pins are inserted. Next, wires and pins are inserted on the calcaneum and metatarsals and fixed, respectively, to the hindfoot arch and forefoot arch.

For peri-articular ankle fractures

We apply the frame with patient supine in a traction table.

Pilon and malleolar fractures are caused by impaction of the convex surface of the talus on the concave surface of the tibia [Figure 6]a]. [10] A comminuted osteochondral fracture develops in the tibial plafond. As the main articular fragments remains attached to the periosteal-capsular envelope, traction across the joint tends to reduce the fracture fragments; this is the basis of reduction by ligamentotaxis [Figure 6]b].

Figure 6: Mechanism of periarticular (pilon and bimalleolar) fractures and mechanism of ligamentotaxis

An inverted U-shaped wire through the calcaneum gives traction and stabilizes the limb and aligns the fragments. Under image intensifier control, the unreduced intra-articular fragments are mobilized percutaneously or by minimal incisions, with a 2.5-3 mm wire as a joystick, and fixed with wires olive wires or screws [Figure 7]a]. [5],[6],[11],[12],[13],[14],[15]

The prebuilt frame is then applied, first fixing the base, then the bridge is fixed to the calcaneum or foot, and finally the wires fixing the articular fragments are attached to the anchoring ring [Figure 7]b].

As an alternative, the initial traction can be done with the frame: The base is fixed to the tibia, then the bridge to the calcaneum, performing ligamentotaxis. Under image intensifier control, the unreduced intra-articular fragments are mobilized and fixed as above.

Special frames

For correction of idiopathic cavus foot

Idiopathic cavus foot can be corrected with a frame without the tibial base, including only the rear foot and forefoot half-rings [Figure 8]a and b].

Neurological cavus foot (either paralytic or spastic) must be corrected with the standard frame with a V osteotomy to avoid relapses.

For ankle arthrodesis

For ankle arthrodesis we use the standard frame for peri-articular fractures. After fixing it, ankle arthrodiastasis is done between the tibial base and the calcaneal bridge and a heavy caliber drill (6-8 mm) is introduced anteriorly through a 10 mm incision and cartilage is destroyed [Figure 9]a].

Arthrodiastasis is performed to 3-5 mm so that sub-talar join is not compressed and two pair of smooth wires are inserted transversally, two in the tibia and two in talus and fixed to the anchoring ring after tensioning [Figure 9]b].

For treatment of lower limb vascular insufficiency and charcot foot

A standard frame is used for correction of foot deformity.

A proximal tibial longitudinal osteotomy is done using multiple drill holes and an osteotome to cut the anterior cortex and crack the posterior cortex by levering the osteotome. Two holes are made with a 4 mm drill bit on the lateral tibia opposite to the osteotomy zone. Two olive wires are driven through those holes and fixed with a traction device to the frame [Figure 10]a].

The increase of vascular flow to the limb distal to the regenerate will improve trophic soft tissue lesions and cure trophic ulcers.

Ambulatory corrections of the frame

Correction of a congenital, acquired, or residual deformity after fracture fixation (due to malunion or bone loss) can be done in the ambulatory period, beginning 10 days after frame application. This includes axis correction, lengthening, and rotational correction and is achieved by applying hinges and motor rods to the initial frame on an outpatient basis.

Planning of those modifications can be done manually or computer assisted. The first technique is based on geometrical data, drawn on a template of the deformed, and normal segment, which permits to find the hinge points, speed, and duration of correction. [16],[17] Computer assisted technique [18] is based on the measurement of spatial position of determined points of the deformed and normal bone structure, on a special computer software, prepared to determine the location of rings and hinge points, speed and duration of correction over the motor rods. [16]

Although theoretically less accurate, we prefer to use the manual planning, because it is cheaper, always available, fast to perform, and with less factors of error, as it permits "fitting by the best try," introducing small changes over the located hinge point.

To correct an axial deformity alone or combined with shortening

On a radiograph template on the plane of the deformity, draw the axis of the tibial diaphysis (bb') and of the distal epiphysis (cc'), a perpendicular to the articular surface (aa'), finding the center of rotation of angulation (d') [Figure 11]a]. The angle of deformity is c'd'b'

Superimpose the normal bone template on the deformed bone template. Draw the line joining the medial malleolus (in this example) of deformed bone to the medial malleolus of normal bone. (ee') [Figure 12]a]. Draw the perpendicular on the middle of that line (ff')

The point X were the two lines dd' and ff' intersects, is the hinge point which will simultaneously correct shortening and axial deformity [Figure 12]b]

To transfer the hinge point from the template to the frame on the patient's leg, measure on the template two coordinates, from the hinge point to 2 well-defined structures and transpose them to the patient leg/frame assembly, reconstructing the hinge point in a 3D environment

Connect the two rings near the deformity with two hinges centered on the derived 3D hinge point, with a rotation axis perpendicular to the plane of the deformity [Figure 13]a]. Assemble a motor rod on the opposite side, and then dismantle the previous connecting rods in between the two rings. Rotating the motor rod at a proper speed and duration will correct simultaneously the shortening and axis deviation [Figure 13]b].

Figure 11: Planning for correction of axial deformity. Drawing the bisector of the complementary deformity angle

To calculate the rate of lengthening or correction [Figure 14]a], draw a straight line joining the hinge point, (a) the concave cortex (b) and the motor rod. (c) Perpendicular to the b point, draw a line, representing 1 unit of lengthening (1 cm = 1 mm/day). Drawing a straight line from the hinge point and passing by the top of the unit b, will indicate over c the velocity of lengthening (2 cm = 2 mm/day). On this example, one must do 2 mm/day on the rod to get 1 mm on the concave cortex, which represents a speed of 2 fold Ό turn 4 times a day.

To calculate the duration of lengthening or correction [Figure 14]b], draw the angle of deformity with the vertex over one of the hinges, finding over the motor rod, the lengthening distance (ab = 7 cm). The duration of lengthening and correction on this example will be 35 days (70 mm: 2 mm = 35 mm). This means that after 35 days of × 2 Ό turn, × 4 times a day, one will get the simulated lengthening and simultaneous axial correction.

This deformity can be corrected at about 10 days after frame application if it is the only residual deformity, or before maturation of the bone regenerates after an axial correction and lengthening.

On a radiograph template on the plane of the deformity, draw the axis lines of the two segments of bone (aa' and bb'), as above and measure the amount of axis translation [Figure 15]a].

Connect the two rings near the deformity with 4 rods: Two with a cylinder that slides on a horizontal rod mounted as a bridge on the other ring, and other two with a gliding clamp and traction rods over one of the rings, oriented on the direction of the pretended correction [Figure 15]a].

Rotating the nuts at the standard speed of Ό turn 4 times a day, will correct the translation deformity [Figure 15]b].

Figure 15: (a) Construct is applied with 3 to 4 connections. (b) Translation is done gradually in chronic cases at the rate of one-fourth mm 4-times a day

This deformity can be also corrected at about 10 days after frame application if it is the only residual deformity, or before maturation of the bone regenerates after an axial correction and lengthening.

Rotational deformity is measured clinically or based on a CT scan.

The basic frame device is made up of two rings connected by three short rods, each with a sliding foot on one ring and a traction device, which permits a rotation movement between the two rings. This device must be assembled between the two rings near the deformity, with short plates, in a way that its center of rotation coincides with the center of the tibia [Figure 16]a].

Rotating the nuts of the traction device at the standard speed of Ό turn 4 times a day during a period calculated as on [Figure 14]b, will correct the rotational deformity [Figure 16]b].

A preassembled Ilizarov frame was applied, including a base with two rings on the tibia and an arch on the calcaneum. Ligamentotaxis was done, reduction and fixation of medial malleolus and then of the tibio-fibular synostosis were achieved percutaneously with olive wires. Three weeks later, the calcaneum arch was removed and partial weight bearing and movement was begun [Figure 17]b].

Radiological and clinical images at 1 year of follow-up [Figure 17]c].

A preassembled Ilizarov frame was applied including a base with two rings on the tibia a bridge to the calcaneum and an anchoring ring at the level of ankle [Figure 18]b]. Initially arthrodiastasis was done to open the ankle joint, an 8 mm drill was introduced anteriorly and both articular surfaces were cut out by drilling. Then acute compression was established using two pairs of smooth wires in talus and tibia, with some arthrodiastasis left to protect the sub-talar joint [Figure 18]c].

Radiological and clinical images at 1.5 years of follow-up [Figure 18]d].

A 6-year-old girl presented with a relapsed left clubfoot, treated initially with manipulation and casting, and later operated with a postero-medial release by Cincinnati method [Figure 19]a].

Percutaneous Achilles tenotomy and plantar fasciotomy were performed.

A preassembled unconstrained Ilizarov frame was applied, including a base with two rings on the tibia, and arch on the calcaneum and another arch on the metatarsus. Two motor rods were applied between the base and calcaneal arch to correct hindfoot varus and equinus, one motor rod in between calcaneal and metatarsal arches to correct forefoot adductus, and another motor rod in between base and metatarsal arch, to correct forefoot equinus. If forefoot supination existed, two motor rods will be connected here to derotate the forefoot [Figure 19]b].

Figure 19: (a) A case of relapsed left clubfoot (6-year-old girl). (b) Use of an unconstrained frame for the correction of deformities. (c) Radiograph and clinical picture showing complete correction of deformities (2 year follow-up)

This frame has no bars or hinges on the lateral aspect of the frame because the hinge points are the foot joints themselves. One of the main characteristics of this methodology is the ability to lengthen the foot to its original dimensions. We use this type of frame, we call open frame in children with <13-15 years old with mobile joints.

Treatment lasted for 3 months: 1 month for correction with the frame, 1 month with the frame static, and 1 month with a plaster boot. After that the patient used a night splint until the end of growth.

Radiological and clinical images at 2 years of follow-up [Figure 19]c].

Correction of club foot sequel in adulthood

A 40-year-old female presented with neglected bilateral clubfoot along with destruction of the talus [Figure 20]a].

A constrained frame was planned with a base with two rings on proximal and medial tibia, a distal ring to do a tibial lengthening, a half ring on the calcaneum, and other on metatarsal bones to do rear foot and forefoot correction [Figure 20]b].

Corticotomy of distal tibia and V osteotomy of calcaneum and mid tarsus was done, plantar fasciotomy and pinning of the toes was also performed [Figure 20]c].

Clinical and radiological images at 2 years of follow-up [Figure 20]d].

A preassembled unconstrained Ilizarov frame was applied, including a base with two rings on the tibia, and arch on the calcaneum and another arch on the metatarsus. Two motor rods were applied between the base and calcaneal arch to correct hindfoot varus and equinus, one motor rod in between calcaneal and metatarsal arches to correct forefoot adductus, and another motor rod in between base and metatarsal arch, to correct forefoot equinus [Figure 22]b].

Figure 22: (a) 13-year-old with Cerebral palsy with Equino-cavus deformity of right foot. (b) Application of unconstrained frame with a medial motor for varus and an anterior and posterior motor equinus. (c) Final appearance of foot and radiograph after treatment (2 year follow-up)

This frame has no bars or hinges on the lateral aspect of the frame because the hinge points are the foot joints themselves. One of the main characteristics of this methodology is the ability to lengthen the foot to its original dimensions.

Treatment lasted for 3 months: 1 month for correction with the frame, 1 month with the frame static, and 1 month with a plaster boot. After that the patient used a night splint until the end of growth.

Clinical and radiological images at 2 years of follow-up [Figure 22]c].

A constrained Ilizarov frame was applied to correct the deformities at four levels: Proximal tibial lengthening, esthetic widening of the leg with medial longitudinal corticotomy of the tibia and medial transport of 2 cm, correction of the hindfoot deformity with a calcaneum corticotomy and correction of forefoot deformity with a mid-tarsal corticotomy and gradual correction [Figure 23]b].

The treatment lasted for 5 months with deformities corrected and esthetic improvement of the foot.

Clinical and radiological images at 2 years of follow-up [Figure 23]c].

Correction of myelomeningocele sequel of leg and foot

A 15-year-old male presented with myelomeningocele sequel with shortening and valgus of the leg and multi-operated equinus-adductus short foot with a plantar ulcer [Figure 24]a].

A constrained Ilizarov frame was preassembled to simultaneously correct the valgus and shortening of the leg and the equinus-adductus short foot, acting over a proximal tibial corticotomy, and a V osteotomy of the calcaneum and tarsus. Stabilization of toes was done by pinning with wires [Figure 24]b].

Figure 24: (a) A case of myelomeningocoele sequel with equinus-adductus short foot, shortening and valgus of leg, with plantar ulcer. (b) Application of constrained Ilizarov frame for addressing the problems. (c) 1 year follow-up clinical and radiographic images

A constrained Ilizarov frame was assembled to correct the foot through a V osteotomy of calcaneum and tarsus. Pinning of the toes was done with smooth wires [Figure 25]b].

Figure 25: (a) Bilateral arthrogrypotic feet with cavo-equino-adductus in a 42 year old. (b) Application of a constrained Ilizarov frame with V osteotomy of calcaneum. (c) Radiograph and clinical image at 2 year follow-up

Clinical and radiological images at 2 years of follow-up [Figure 25]c].

Correction and treatment of charcot foot

A 72-year-old female suffering from Charcot neuro-arthropathy associated with a vascular insufficiency of distal left limb secondary to a diabetic micro-vasculopathy. She presented with a medial ankle dislocation and a trophic ulcer of the lateral side of the leg [Figure 26]a].

We planned to do simultaneous correction of foot and vascular stimulation of the limb with medial transport after a longitudinal corticotomy of the proximal tibia using a constrained Ilizarov frame with hinges [Figure 26]b].

Foot was translated under the tibia and arthrodesis was done by ankle joint compression [Figure 26]b].

Figure 26: (a) Trophic ulcer over lateral aspect of ankle following a medial ankle dislocation in a 72-year-old female with charcot neuroarthropathy secondary to diabetic vasculopathy induced distal limb ischemia. (b) A constrained frame is applied with a goal to address vascular problem and correction of foot simultaneously. (c) Evolution of the healing ulcer to complete healing at 45 days and final appearance of limb